And like those films, it all comes flowing onto the screen during a single, highly memorable moment. Beverly Marsh (Chastain) is being stalked by the otherworldly clown Pennywise when she finds herself trapped in a bathroom stall that quickly begins filling up with blood, first over her legs, then her chest, then up toward her eyes.

She got her own slice of revenge on director Andy Muschietti and his wife/co-producer Barbara Muschietti, though.

"I have some pictures from the end when they finally let me out of the tank of hugging Andy and Barbara," she revealed. "And smearing them with the slime that I was in for like 16 hours. That was gross, but also it was really disgusting to then wear it for the rest of the movie. I mean, it looks good, when I watch the film I'm like, 'It looks cool that she's still covered in blood, but not comfy.’"

The scene feels like an homage to two famous moments from previous Stephen King adaptations: Carrie (1976), in which Sissy Spacek's crimson-haired teen gets drenched with pig's blood at the prom; and The Shining (1980), in which the elevator at the Overlook Hotel unleashes a flood of blood. When a frightening figure tries to barge into the stall and yells, “Here’s Johnny!,” it only drives home the callback.

Andy, however, downplays the connection.

"I think it comes from the story itself," he said. "Blood is a bit of symbol of everything that traumatized Beverly growing up."

It Chapter Two is now playing. Watch James McAvoy talk about his encounter with Stephen King: